private Point2d InternalGetFocus(bool primary)
{
double majrad = MajorRadius;
double minrad = majrad * sigratio;
double fdist = Math.Sqrt(majrad * majrad - minrad * minrad);
return(center.Polar(Rotation, fdist * (primary ? 1.0:-1.0)));
}
public override Point2d ClosestPoint(Point2d from)
{
if (Linear)
{
return(new Line2d(start, end).ClosestPoint(from));
}
Point2d ce = Center;
Point2d oncirc = ce.Polar(ce.Angle(from), Radius);
if (IsCirclePointOnArc(oncirc))
{
return(oncirc);
}
return(from.ClosestPoint(start, end));
}
public override Point2d PointAt(double t)
{
return(center.Polar(t * MathUtil.Deg360, radius));
}